The blast came a day after rare sectarian attacks in three Afghan cities killed 59 people, and refocused attention on the fragile Afghan security situation.

Afghans have previously been spared the large-scale sectarian attacks that regularly trouble Iraq and neighboring Pakistan, but now face the grim prospect of a new type of bloodshed being added to the dangers of daily life.

The NATO-led International Security Assistance Force (ISAF), responsible for security across much of the country, says it is winning the war against the Taliban.

The interior ministry has blamed "the Taliban and terrorists", without giving further details, while the Taliban strongly condemned the bombings.

Afghanistan has said that it will not be able to afford the army and police force it needs after 2014 without international help, and the December 6’s attack is likely to reinforce fears about the ability of Afghan forces to cope with violence after ISAF has fully handed over security.